It's wrong because it's illegal and it's illegal because it's wrong.

"Understanding why criminalizing abortion won’t end abortion takes only a bit of simple reasoning:"

Oh, we're back to that one. I thought we had dispensed with that.

Criminalizing murder, rape, and robbery didn't end them either. Should we decriminalize them, then?

Social theorists say that ordered civilization is a precarious balance between anarchy and barbarism. Ordered society and the social contract are efforts to keep the most reprehensible human behaviors in check to a level such that the society survives. The social contract is founded on the basic tenets of right and wrong. We don't have laws because we think the law will cause everyone to stop the behavior. We have laws to indicate the behavior will have swift and sure consequences. We formulate the consequences such that most civilized humans will find them abhorrent enough to avoid the behavior. To suggest that we should not have a law prohibiting a reprehensible behavior simply because it will not stop the behavior is circular reasoning.